This invention relates to body monitoring apparatus, such as, for example, ECG monitoring apparatus.
Body monitoring apparatus generally includes physiological sensors, a monitoring device and cables connecting the sensors to the monitoring device. The sensors are attached to a patient""s body to detect physiological signals and may be, for example, electrocardiogram (ECG) electrodes, electroencephalogram (EEG) electrodes or blood oxygen sensors. For example, in ECG monitoring apparatus an electrocardiogram signal is measured as the difference in potential between a set of electrodes placed externally on the body of the patient. This allows the cardiac activity to be measured.
In ambulatory monitoring the complete electronic apparatus is miniaturised and battery operated, adapted for wearing on the patient""s body. WO94/26164 describes one known ambulatory monitoring apparatus, and is incorporated herein by reference.
In all types of body monitoring apparatus it is advantageous for safety reasons that the patient is electrically isolated from the apparatus in use. In particular that access to the power source and other electrical connections in the monitoring device are prevented.
According to the invention, there is provided body monitoring apparatus including a sensor device for detecting physiological signals and a monitoring device, the monitoring device including a first part of a casing and an electronics module, the sensor device including a second part of a casing, wherein a completed casing which surrounds the electronics module is provided by the first and second parts attached together when the sensor device is connected to the monitoring device.
Of the completed casing the first and second parts are the only detachable parts. These parts are designed to be detached by only authorised personnel and not the user. The user will regard the device as one sealed unit.
Preferably, the sensor device includes means for sensing potentials at points on the patient""s body. In the embodiment the sensing means is permanently attached or incorporated into the sensor device. It is not possible to change the sensing means without detaching the sensor device from the monitoring device, i.e. splitting the completed casing apart.
Advantageously, the completed casing is watertight. Therefore the device can continue to operate even when exposed to moisture. Because the casing has only two parts, only one watertight seal is required.
The electronics module of the monitoring device in the embodiment includes a power source which can only be removed when the sensor device is not connected to the monitoring device. Detaching the sensor device from the monitoring device in the embodiment automatically shuts down the electronics. Therefore, the device cannot be damaged by removing the power source while the electronics are fully operational. Also, because the power source is inaccessible to the patient, a high power power source can be included in the apparatus.
The present invention also relates to a cabling device, a sensor device and a monitoring device all for use in the body monitoring apparatus as defined above.